1 files changed, 63 insertions, 0 deletions

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 4b384c907027..d7b99a737496 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -83,6 +83,31 @@ static int symbol_by_offset(const void *key, const struct rb_node *node)
 	return 0;
 }
 
+struct symbol_hole {
+	unsigned long key;
+	const struct symbol *sym;
+};
+
+/*
+ * Find !section symbol where @offset is after it.
+ */
+static int symbol_hole_by_offset(const void *key, const struct rb_node *node)
+{
+	const struct symbol *s = rb_entry(node, struct symbol, node);
+	struct symbol_hole *sh = (void *)key;
+
+	if (sh->key < s->offset)
+		return -1;
+
+	if (sh->key >= s->offset + s->len) {
+		if (s->type != STT_SECTION)
+			sh->sym = s;
+		return 1;
+	}
+
+	return 0;
+}
+
 struct section *find_section_by_name(const struct elf *elf, const char *name)
 {
 	struct section *sec;
@@ -162,6 +187,41 @@ struct symbol *find_symbol_containing(const struct section *sec, unsigned long o
 	return NULL;
 }
 
+/*
+ * Returns size of hole starting at @offset.
+ */
+int find_symbol_hole_containing(const struct section *sec, unsigned long offset)
+{
+	struct symbol_hole hole = {
+		.key = offset,
+		.sym = NULL,
+	};
+	struct rb_node *n;
+	struct symbol *s;
+
+	/*
+	 * Find the rightmost symbol for which @offset is after it.
+	 */
+	n = rb_find(&hole, &sec->symbol_tree, symbol_hole_by_offset);
+
+	/* found a symbol that contains @offset */
+	if (n)
+		return 0; /* not a hole */
+
+	/* didn't find a symbol for which @offset is after it */
+	if (!hole.sym)
+		return 0; /* not a hole */
+
+	/* @offset >= sym->offset + sym->len, find symbol after it */
+	n = rb_next(&hole.sym->node);
+	if (!n)
+		return -1; /* until end of address space */
+
+	/* hole until start of next symbol */
+	s = rb_entry(n, struct symbol, node);
+	return s->offset - offset;
+}
+
 struct symbol *find_func_containing(struct section *sec, unsigned long offset)
 {
 	struct rb_node *node;
@@ -1019,6 +1079,9 @@ int elf_write(struct elf *elf)
 	struct section *sec;
 	Elf_Scn *s;
 
+	if (dryrun)
+		return 0;
+
 	/* Update changed relocation sections and section headers: */
 	list_for_each_entry(sec, &elf->sections, list) {
 		if (sec->changed) {